These prices seem reasonable, so I'm not sure why brain scans are considered a big deal. (Other than MRI's noise factor and other scans' contrast substances, if any)

The problem with starting with low blood sugar or such, is that it can take weeks or months of tweaking a diet to even find out if that is the cause, much less correct it. Trying first one 'diagnosis by treatment' and then another, can eat up a lot of time.

Um...I'm not sure what you are thinking there. Low blood sugar is strictly determined thru a blood test. There are no "weeks of tweaking a diet." Take my word for it, my blood sugar was 58 - and that was not a fasting test! So, It's pretty cut and dried - as are many issues - the cure is just to eat regularly. So I don't understand why you think it's so complicated.